1. Field of the Invention
The present invention relates to a printing system formed of a printing apparatus and a host apparatus thereof, and also to a printing apparatus for outputting print data supplied from a host apparatus.
2. Description of the Related Art
Hitherto, in a printing system formed of a printing apparatus and a host apparatus thereof and having at least two methods for transferring print data, the following control is required when the transfer method is changed between the host apparatus and the printing apparatus. For correctly receiving data transferred from the host apparatus or the printing apparatus, almost all the transfer data is required to be analyzed in order to monitor whether the transfer method has been changed.
However, the above-described analyzing operation performed on almost all the print data results in a waste of the capacity of the printing apparatus (or the printing system), because it is irrelevant to the actual printing operation, thereby lowering the efficiency of the overall printing operation.
Accordingly, in order to solve the above problem, it is an object of the present invention to provide a printing system and a printing apparatus in which the efficiency of the overall printing operation can be enhanced by simplifying the processing for monitoring the change of the transfer methods.
In order to achieve the above object, according to one aspect of the present invention, there is provided a printing system including a printing apparatus and a host apparatus of the printing apparatus. In the printing system, print data or control data is transferred between the printing apparatus and the host apparatus in accordance with at least two transfer methods. The printing system includes prediction means for predicting a change of the transfer method immediately after a specific state has passed. Control means controls the host apparatus or the printing apparatus to change the transfer method when the other apparatus changes the transfer method based on a result predicted by the prediction means.
In the aforementioned printing system, upon receiving a device identification request defined in IEEE1284-1994 from the host apparatus, the prediction means may predict a change of the transfer method, and the control means may cause the transfer method to become ready for a change immediately after the device identification request has been received.
In the aforementioned printing system, upon starting or completing the transferring of device identification data to the host apparatus in response to a device identification request defined in IEEE1284-1994 from the host apparatus, the prediction means may predict a change of the transfer method, and the control means may cause the transfer method to become ready for a change immediately after said printing apparatus starts or finishes transferring the device identification data to said host apparatus.
In the above case, the control means may cause the transfer method to become ready for a change upon completing the transferring of the device identification data to the host apparatus if specific data is contained in the device identification data.
In the aforementioned printing system, upon issuing an initializing signal on an interface in accordance with an instruction from the host apparatus, the prediction means may predict a change of the transfer method, and the control means may cause the transfer method to become ready for a change immediately after executing processing for the initializing signal.
In the aforementioned printing system, upon initializing the printing apparatus in accordance with an instruction from operation means of the printing apparatus, the prediction means may predict a change of the transfer method, and the control means may cause the transfer method to become ready for a change immediately after the printing apparatus has been initialized.
In the aforementioned printing system, upon resupplying power to the printing system, the prediction means may predict a change of the transfer method, and the control means may cause the transfer method to become ready for a change upon completion of the resupply of power.
In the aforementioned printing system, upon receiving an instruction from operation means of the printing apparatus or the host apparatus, the prediction means may predict a change of the transfer method, and the control means may cause the transfer method to become ready for a change immediately after the operation means has been operated.
In the aforementioned printing system, upon transferring a specific command from the host apparatus or the printing apparatus and analyzing the specific command by the host apparatus or the printing apparatus, the prediction means may predict of a change of the transfer method, and the control means may cause the transfer method to become ready for a change immediately after the specific command has been analyzed.
In the above case, an analysis of data transferred from the host apparatus or the printing apparatus continues until a predetermined amount of data has been received after the transfer method has become ready for a change. In this case, the predetermined amount of data to be analyzed may be preset by operation means. Alternatively, the predetermined amount of data to be analyzed may be preset by a command pretransmitted from the host apparatus or the printing apparatus.
In the aforementioned printing system, the currently used transfer method may not be changed, but may be maintained, if the print data or the control data is transferred from the host apparatus or the printing apparatus in accordance with the currently used transfer method even if the transfer method becomes ready for a change.
In the aforementioned printing system, the currently used transfer method may not be changed, but may be maintained, if a determination of whether the transfer method has been changed has not been made for a predetermined period because there is only a small amount of print data or control data transferred from the host apparatus or the printing apparatus after the transfer method has become ready for a change. In this case, the predetermined period may be preset by operation means, or may be preset by a command pretransmitted from the host apparatus or the printing apparatus.
According to another aspect of the present invention, there is provided a printing apparatus for transferring print data or control data to a host apparatus in accordance with at least two transfer methods, and for outputting the print data supplied from the host apparatus. The printing apparatus includes prediction means for predicting a change of the transfer method immediately after a specific state has passed. Control means causes the transfer method to become ready for a change based on a result predicted by the prediction means.
In the aforementioned printing apparatus, upon receiving a device identification request defined in IEEE1284-1994 from the host apparatus, the prediction means may predict a change of the transfer method, and the control means may cause the transfer method to become ready for a change immediately after the device identification request has been received.
In the aforementioned printing apparatus, upon starting or completing the transferring of device identification data to the host apparatus in response to a device identification request defined in IEEE1284-1994 from the host apparatus, the prediction means may predict a change of the transfer method, and the control means may cause the transfer method to become ready for a change immediately after starting or finishing transferring the device identification data to the host apparatus.
In the above case, the control means may cause the transfer method to become ready for a change upon completing the transferring of the device identification data to the host apparatus if specific data is contained in the device identification data.
In the aforementioned printing apparatus, upon issuing an initializing signal on an interface in accordance with an instruction from the host apparatus, the prediction means may predict a change of the transfer method, and the control means may cause the transfer method to become ready for a change immediately after executing processing for the initializing signal.
The aforementioned printing apparatus may further include operation means for performing an operation for printing. Upon initializing the printing apparatus in accordance with an instruction from the operation means, the prediction means may predict a change of the transfer method, and the control means may cause the transfer method to become ready for a change immediately after the printing apparatus has been initialized.
In the aforementioned printing apparatus, upon resupplying power to the printing apparatus, the prediction means may predict a change of the transfer method, and the control means may cause the transfer method to become ready for a change upon completion of the resupply of power.
The aforementioned printing apparatus may further include operation means for performing an operation for printing. Upon receiving an instruction from the operation means, the prediction means may predict a change of the transfer method, and the control means may cause the transfer method to become ready for a change immediately after the operation means has been operated.
In the aforementioned printing apparatus, upon transferring a specific command from the host apparatus and analyzing the specific command, the prediction means may predict a change of the transfer method, and the control means may cause the transfer method to become ready for a change immediately after the specific command has been analyzed.
In the above case, an analysis of data transferred from the host apparatus may continue until a predetermined amount of data has been received after the transfer method has become ready for a change. In this case, the printing apparatus may further include operation means for performing an operation for printing. The predetermined amount of data to be analyzed may be preset by the operation means, or may be preset by a command pretransmitted from the host apparatus.
In the aforementioned printing apparatus, the currently used transfer method may not be changed, but may be maintained, if the print data or the control data is transferred from the host apparatus in accordance with the currently used transfer method even if the transfer method becomes ready for a change.
In the aforementioned printing apparatus, the currently used transfer method may not be changed, but may be maintained, if a determination of whether the transfer method has been changed has not been made for a predetermined period because there is only a small amount of print data or control data transferred from the host apparatus after the transfer method has become ready for a change.
In the above case, the printing apparatus may further include operation means for performing an operation for printing. The predetermined period may be preset by the operation means, or may be preset by a command pretransmitted from the host apparatus.
Further objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings.